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WorksheetsELEC 17001
Total questions: 30
Worksheet time: 23mins
Class II electrical equipment exposures are designed to resist the:
Ingress of gases
Ingress of liquids and dust
Ingress of solids only
Ingress of air
Define the term grounded conductor.
The conductor that carries current to the load
The conductor that is always live
The system or circuit conductor that is intentionally grounded
The conductor that connects to the neutral bus
Fittings with machine faces must be used on:
Class 1, Zone 0
Class 2, Zone 1
Class 3, Zone 2
Class 4, Zone 0
Electrical equipment installed in an explosive atmosphere location shall be marked:
Exd
Ex
Exp
Exi
An overload device protects a motor from overcurrents which are caused by:
Short circuits only
Ground faults only
Blocked rotors and increased loads
Voltage spikes
A Class III location is defined as:
Areas with flammable gases
Areas with flammable liquids
Areas where there is a danger of explosion due to the presence of fibers and flyings
Areas with high humidity
A submersible pump system for a water well operates at 120V. Determine the type of receptacle that the pump must be connected to:
Standard receptacle
GFCI
AFCI
Weatherproof receptacle
Identify the most suitable type of fitting that can be used with EMT conduit in a location that is damp or corrosive.
Standard fitting
Weatherproof fitting
Corrosion-resistant fitting
Explosion-proof fitting
The circuit protective device which can protect circuits from arcing faults describes a/an:
GFCI
AFCI
Circuit breaker
Fuse
How shall AC systems be grounded?
On the load side of the service disconnect
On the line side of the service disconnect
At the neutral bus
At the main panel
According to the NEC/T&T electric codes, conductors that supply a single motor used in a continuous duty application shall have an ampacity of not less than ______ percent of the motor full-load current (FLC) rating.
100
115
125
150
A device which can be manually operated or operates automatically at pre-determined overloads and short circuit currents defines a/an:
Fuse
Relay
Circuit breaker
Disconnect switch
What are the wiring methods for Class II environments?
NM cable
PVC conduit
RMC conduit
EMT conduit
Weatherproof fittings can be used in __________ locations.
Class 1, Zone 0
Class 1, Zone 1
Class 1, Zone 2
Class 2, Zone 0
Indoor dielectric equipment containing more than 23 L of liquid in one tank or more than ______ L in a group of tanks shall be located in an electrical equipment vault.
69
50
100
120
In a fuel dispensing Class 1 Division 1 location, conduit seals for enclosures shall normally be installed within a distance from the enclosure of:
6 inches
12 inches
24 inches
18 inches
In bulk storage plants, the internal space of a tank shall be considered a ________ location.
Class 1, Zone 1
Class 2, Zone 0
Class 3, Zone 0
Class 1, Zone 0
Electrical equipment installed in Class II atmospheres must be:
Waterproof, explosion-proof
Dust-tight, corrosion-resistant
Weatherproof, ignition-proof
Dust-proof, ignition-proof
Solidly grounded systems have a grounding electrode conductor and a grounding electrode which are the main parts of its grounding system. The impedance of these systems shall be:
Not more than 0.5Ω
Not more than 1Ω
Not more than 2Ω
Not more than 5Ω
A three-phase 15HP motor is connected to a 460V supply and has a FLC of 21A. If the overcurrent device is a fuse, then the overload must be set at:
100% of 21A
150% of 21A
200% of 21A
300% of 21A
According to the Trinidad and Tobago wiring code (TTS-171-PART1-2015), every motor starting equipment must be provided with a disconnecting means which will open all ungrounded conductors. The rating of the disconnecting means shall be rated:
Not less than 100% of the full load current rating of the motor
Not less than 115% of the full load current rating of the motor
Not less than 125% of the full load current rating of the motor
Not less than 150% of the full load current rating of the motor
The minimum clearance between non-insulated bus bars and enclosures in switchgears is:
100MM
150MM
200MM
250MM
A Class I location is defined as:
Areas where there is a danger of explosion due to the presence of flammable vapors, gases, and liquids
Areas with flammable dust
Areas with fibers and flyings
Areas with high humidity
A Class II location is defined as:
Areas with flammable gases
Areas where there is a danger of explosion due to the presence of flammable dust
Areas with fibers and flyings
Areas with high humidity
Which circuit protective device will automatically operate when current draw exceeds its normal operating limit?
Overcurrent
GFCI
AFCI
Disconnect switch
What properties must wiring in Class III environments have?
Waterproof, explosion-proof
Dust-tight, corrosion-resistant
Weatherproof, ignition-proof
Fiber-tight, ignition-proof
In a heating element system, the part responsible for generating heat is called the:
Coil
Terminal
Element
Insulator
A three-phase 15HP motor is connected to a 460V supply and has a FLC of 21A. If the service factor on the nameplate is 1.15, then the overload must be set at:
100% of 21A
115% of 21A
125% of 21A
150% of 21A
What is the main purpose of grounding?
To improve electrical efficiency
To protect life from danger of shock
To reduce energy consumption
To increase voltage stability
GFCI devices operate when:
There is a voltage drop
There is a current difference of 10 milliamperes
There is a short circuit
There is a current difference of 4 to 6 milliamperes
